Lubricant



Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE LUBRICANT Clarence M. Loane and Bernard H. Shoemaker,

Hammond, Ind., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Original application September 17, 1937, Serial No. 164,310, which is a division of application Serial No. 108,832, November 2, 1936. Divided and this application December 18, 1939,. Serial No. 309,828

13 Claims.

This invention relates to lubricants and, in particular, to addition agents imparting to lubricants improved properties. i Our invention has particular utility in prevent ing and/or inhibiting the corrosion of hard metal alloy bearing such as copper-lead, cad- 'mium-nickel; and cadmium-silver bearings which, to a large extent, have replaced soft metal bearings such as Babbitt metal in the trend toward internal combustion engines having high compression ratios and having increased acceleration and increased speed characteristics. The use of the hard metal bearings has created lubrication and corrosion problems, particularly in connection with highly refined oils some of which may be very corrosive to the "hard metal" bearings.

By highly refined lubricating oils we mean viscous oils which have a minimum viscosit: in the range of S. A. E. 10 oils and which have been subjected to such refining processes, for example,

. solvent extraction, that the paraflinicity of the oil is markedly increased. It has been found that highly refined lubricating oils cause corrosion to alloy bearings of the cadmium-silver type to the extent of 5 nag/cm. and even greater when such bearings are submerged for 25 hours or less in an air agitated oil which has been preoxidized at about 340 F. for 25 to 50 hours. The motor oils 3 may be highly refined lubricating oils as such or mixtures of highly refined lubricating oilswith in which R1, R2, R3 and R4 may be hydrogen or an alkyl radical, or an alkylene radical or an aryl radical or other hydrocarbon radical such as 'Cetyl pseudo thio urea, Lauryl pseudo thio urea, Naphthyl pseudo thio urea.

I We have also found that the condensation products of a thio urea and mustard oil are very efiective for the purposescontemplated within ourinvention. These condensation products, which have the general formula NRs CaHsNCS-HSC Ra in which R5, R6 and R7 may be hydrogen, an alkyl radical, an alkylene radical or an aryl radical or other hydrocarbon radicals, may be prepared by heating together equivalent molecular quantities of mustard oil and thiourea on a steam bath until the odor of the mustard oil is no longer detected. The symmetrical amyl allyl thiourea-mustard oil condensation product having the formula CsHn and the thio carbanilide-mustard oil condensation product having the formula N'-C6H5 r CaHs prepared as above described are very efiective.

Since these compounds are'subjected .to high temperature conditions it is highly desirable that compounds of the aforementioned type having boiling points of about 400 F. or greater be used. The effectiveness of compounds of the above type as corrosion inhibitors is demonstrated by the following examples in which they were subjected to one or more difierent sets of conditions, each of which is more severe than those encountered in the actual operation internal combustion engines.

Method L-Bythis method a highly" refined oil, to which the corrosion inhibitor is to be added,

6 is preoxidized for either 25 hours or 50 hours by air agitating the same at about 341 F. The corrosion inhibitor and the weighed bearings are placed in the preoxidized oil and the oil airagitated at about 341 F. The bearings are removed at periodic intervals, washed free of oil and the loss in weight determined.

Method II.-By this method the weighed bearings are placed in a "highly refined oil containing the inhibitor which is air-agitated at about- 15, 341 F. At periodic intervals the bearings are removed from the oil bath, washed free of oil and the loss in weight determined. Each time beiore being replaced in theoil bath the bearings are polished bright and reweighed and again tested for predetermined periods. This method difiers from Method Iin that the test is started with an unoxidized "highly refined oil and the test bear- 1118s are polished at predetermined intervals.

In each of the above methods the oil used was 25 in weightoi more than mg./cm.= was obtained in hours-or less on a cadmium-silver alloy bearing submerged in an air-agitated oil at 340 F., which 011 had been preomdized for 25-50 hours at about 340 F.

In Table I are tabulated the results obtained with representative compounds when tested according to the above described test Method 1.

Table I Loss in mg/crn. inon 3 hrs. 24 hrs.

Control as 43.0 Control +03% cetyl pseudo thiourea 0. 0 0. 0

In Table II are the results obtained with several representative compounds when tested according to the above described test Method H.

v While we have described in detail the use oi the hereinbefore mentioned compounds as corrosion inhibitors in highly" refined lubricating 65 oils, we contemplate the use of up to 10% of these compounds in lubricating oils whether highly refined or not, for the purpose of improving the fllm'strength thereof and to impartto lubricants improved extreme pressure char- 70 acteristics. These compounds may also be used to improve the lubricity and other desirable properties of lubricating oils.

Some of the herelnbefore named compounds may notbe completely soluble in the lubricant,

75 in-which case eflective results are obtained by a motor oil refined to such an extent that a loss suspending the inhibitor in the lubricant by means oi a small amount of a peptizing agent such as aluminum naphthenate, aluminum stearate, etc. I

Thisapplication isa division of our co-pending application Serial Number 164,310 filed September 1'1, 1937, now U. S. Patent No. 209,464, issued July 30, 1940, which is a division of our then co-pending application Serial Number 108,-

832, flled November 2, 1936, and now United States Patent Number 2,160,880, issued June 6, 1939.

We do not limit ourselves to the specific embodiments of our invention herein described except as defined by the appended claims.

We claim:

1. A lubricant containing from about 0.05%

to about 10% of an organic compound selected ijrom the group consisting of (1) pseudo thiourea derivatives having the general formula in which R1, Ra, Ru and R4 are substituents selected .from the group consisting of hydrogen and hydrocarbon radicals and (2) the condensation products of thioureas and mustard oil.

2. A corrosion inhibited lubricating oil adapted for use in the presence of hard metal alloy bearings having the corrosive susceptibility of alloys of the class consisting of cadmium-silver alloys, cadmium-nickel alloys, and copper-lead alloys, comprising a highly refined mineral lubrieating oil normally corrosive to such alloys, and a small but suificient amount to inhibit the corrosion of said alloy bearings of an organic compound selected from the group consisting of (1) pseudo thiourea derivatives having the general formula ni-s-c R! in which R1, Ra, R: and R4 are substituents selected from the group consisting of hydrogen, and hydrocarbon radicals, and (2) the condensation products of thioureas and mustard oil.

3. A lubricant comprising a mineral lubricatmg 011' and irom about 0.05% to about 10% of a pseudo thiourea.

4. A lubricant comprising a mineral lubricating oil normally corrosive to alloys having the,

corrosive susceptibility of alloys of the class consisting of cadmium-silver alloys, cadmium-nickel alloys, and copper-lead alloys, and a pseudo thiourea added in amounts sumclent to render said mineral lubricating oil'non-corrosive to said alloy.

5. A lubricant as described in claim 4 in which the pseudo'thiourea is cetyl pseudo thiourea.

6. A lubricant comprising a mineral lubricating oil normally corrosive to alloys having the corrosive susceptibility of alloys of the class consisting of cadmium-silver alloys, cadmium-nickel alloys, and copper-lead alloys and condensation productof a thiourea and mustard oil added in amounts sumcient to render said mineral lubrieating oil non-corrosive to said alloys.

7. A lubricant as described in claim 6 in which 'he thiourea-mustard oil condensation product has the general formula V 8. A lubricant as described in claim 6 mustard oil having the general formula N-C|Hi \cimNoane-o n 9. The method of preventing the corrosion of v which the thiourea-mustard oil condensation product is a condensation product of thiocarbanalide and in which R1, Ra, R: and mm substituents selected from the group consisting of hydrogen and hydrocarbon radicals, and.(2) the condensation products of thioureas and mustard oil.

10. The method described in claim -9 in which the pseudo thlourea is cetyl pseudo thiourea.

l1. The method described in claim 9 in which th thiourea-mustard oil condensation product is the condensation product of thiocarbanalide and mustard oil havingthe general formula 12. The-method describedin claim 9 in which the thiourea-mustard oil condensation product has the general formula 1a. A lubricant'containing fromabout 0.05% to about 10% of the condensation product of a thiourea. and mustard oil. v

CLARENCE M. LOANE. BERNARD H. SHOEMAKER. 

